Tetrazolium C-oxy-betaine compounds as antifog agents for silver halide photographic emulsions

ABSTRACT

Tetrazolium C-oxy-betaine compounds are effective antifog agents for silver halide photographic emulsions when reactively associated therewith. Such compounds can be incorporated in the photographic element in reactive association with the silver halide emulsion or in a processing bath prior to or during development of emulsion layers.

United States Patent Baldassarri et al.

[4 1 Sept. 30, 1975 TETRAZOLIUM C-OXY-BETAINE COMPOUNDS AS ANTIFOG AGENTS FOR SILVER HALIDE PHOTOGRAPHIC EMULSIONS Inventors: Agostino Baldassarri; Walter Ferro,

both of Savona, ltaly Assignee: Minnesota Mining and Manufacturing Company, St. Paul, Minn.

Filed: Apr. 29, 1974 Appl. No.: 465,185

Foreign Application Priority Data May 7, 1973 Italy 49830/73 US. Cl. 96/76 R; 96/109 Int. Cl. G03C 1/34 Field of Search 96/109, 107, 66.5, 76 R [56] References Cited UNITED STATES PATENTS 3,023,103 2/1962 Dersch et a1 96/109 Primary ExaminerWon H. Louie, Jr. Attorney, Agent, or FirmAleXander, Sell, Steldt & DeLaHunt 57 ABSTRACT 17 Claims, No Drawings TETRAZOLIUM C-OXY-BETAINE COMPOUNDS AS ANTIFOG AGENTS FOR SILVER HALIDE PHOTOGRAPHIC EMULSIONS This invention relates to tetrazolium C-oxy-betaine compounds as antifog agents for silver halide photographic emulsions.

As it is known, the problem of fog, that is the silver reduced in unexposed areas upon development, is one of the most important ones to be solved in the photographic chemistry. This problem has become more critical since high temperature baths are used containing aldehydes as hardening agents.

Various compounds have long been tested and recently some good antifog agents have been described in US. Pat. No. 3,071,465.

We have now found that tetrazolium C-oxy-betaine compounds are very effective agents both used in a photographic element reactively associated with the silver emulsion and in a processing bath adapted for use prior to or during development of emulsion layers. They surprisingly show a very good antifogging effect with a low desensitization effect. They can also be used in combination with high temperature processing baths containing or not aldehydes as hardening agents.

The compounds useful according to the present invention are preferably those represented by the following formula:

or a mesomeric form thereof wherein R is an aryl group. In the practice of this invention, an aryl group is a phenyl group or a naphthyl group. Preferably the phenyl or naphthyl group will not contain more than a total of twelve 12) carbon atoms therein. Substituents, if any, are preferred from halogen, alkyl, alkoxy, perfluoroalkyl, haloalkyl and acyl. The substituents therefore preferably have no more than six (6) carbon atoms when attached to a phenyl ring and no more than two (2) carbon atoms when attached to a naphthyl group.

The phenyl or naphthyl ring may contain more than one of any substituent. The molecular weight of the' aryl group is preferably below 300 and more preferably below 200. g

Accordingly, the invention in one aspect relates to a silver halide emulsion having contacted therewith a tet-.

razolium C-oxy-betaine compound. In another aspect the invention relates to a silver halide photographic element having a silver halide. emulsion layer and having a tetrazolium C-oxy-betaine compound in reactive association therewith (eg in the emulsion layer or a layer adjacent the emulsion layer). The invention in a further aspect relates to a method for inhibiting fog in a silver halide photographic emulsion which comprises contacting said emulsion with a tetrazolium C-oxybetaine compound. The invention further relates to an improved method for processing an exposed silver halide element, which includes treating said element with a series of photographic treatment solutions including a development solution, the improvement comprising contacting said element during said processing with a tetrazolium C-oxy-betaine compound, said compound being contained in said development solution and/or in a pre-development treatment solution. In another aspect the invention relates to a processing solution adapted for use prior to or during development of a silver photographic element, containing or not an aldehyde as hardener, containing a fog inhibiting amount of a tetrazolium C-oxy-betaine compound.

Tetrazolium C-oxy-betaine compounds as a class have been found useful as fog inhibiting agents for silver halide emulsions when reactively associated therewith. It has been found that substituents attached to nitrogen atoms do not substantially vary the capacity of the compounds to inhibit fog.

Examples of tetrazolium C-oxy-betaine compounds according to the present invention are described in Table l, which indicated their preparation methods and yields and describes their chemical-physical characteristics. Table 2 describes some prior art compounds with respect to which comparison tests have been carried out. (DMF in the above tables stands for dimethylformamide Table 1 R N*=N RN--N Solubility Example R m.w N5? EtOH DMF method yield 2 Q-Cl 307.15 165 0.5 2.5 A 46 Table I,-.Cont1'nued I $010511! Example v m.w M.P. EtOH "DMF method yield 11, 335.21 I I56" "l.8 6.3 A' 54 a 266.31 165 .6.3 12.5 A I 72 c1 10 C] 376.05 140. 0.45 .50 D 22 Table 2 R--N+=N C-R x- R'N -'-1-1 Y 1 Solubility Com- R R X- m.w. EtOH DMF pound 4 (a) Hso; 396.43 3.6% 20.2%

(b) CH Br 317.21 l.8% 4.5%

The tetrazolium C-oxy-betaine compounds of the of the corresponding c-nitro-formazanes, according to present invention have been prepared upon oxidation what described by A. W. Nineham, Chem. Review 55 (1955 406 and by F. Bamberger, R. Padova, E. Ormerod, Ann. Chem. 446 (1926), 260-307. Different preparation methods have been followed corresponding to different oxidizing agents; that is to say that the hereinafter illustrated methods respectively correspond to the oxidizing agents: amylnitrite, N-bromosuccinimide, lead acetate, sodium hypochlorite. The C-nitroformazanes have been prepared upon reaction between an aryldiazolium chloride, obtained in a conventional way, and an alkaline nitromethane solution at a temperature ranging from -1 5 to C, in aqueous environment and in the presence of sodium acetate according to what described by E. Bamberger, R. Padova, E. Ormerod, Ann. Chem. 446 (1926) 260-307 and by D.

METHOD c 2,3-di-( 2-ethyl-phenyl-5 )-oxy-tetrazole-betaine (Example No. 5')

ml of water, then cooled. The water was decanted and the remaining solid was finally crystallized first from chloroform/ether and then from 20% aqueous acetone,

M. Hubbard and E. W. Scott 1n J. A. C. S. 65 (1943) thus obtaining white yeuow p y M'P' lsloc/dec. Yield 48% of the calculated yield Said methods will be hereinafter better illustrated with reference to specific examples of preparation. METHOD 1) 2,3-di-(2-chloro-phenyl)-5-oxy-tetrazole-betaine METHOD A (Example No. 9) 2,3-di-phenyl-5-oxy-tetrazolium-betaine (Example No. 0.1 M l f 1 5-(2- h] h 1 3- m 1 formazane, after pulverization, were suspended at 50C in 350 ml of acetic acid and slowly added with sodium 0.075 Moles of l,5-diphenyl-3-nitro-formazane, 0.13 5 hypochlorite (solution: 8% active chlorine) under stirmoles of amyl nitrite and 0.25 moles of acetic acid were ring to decolorize the formazane. 200 ml of sodium hymixed with 250 ml of acetone and refluxed on waterpochlorite were necessary to decolorize completely the bath for 45. Nitrous vapors developed from the soluformazane. The whole was then cooled at 0C, filtered tion and a solid separated. The whole was cooled, the upon aspiration and then poured into 101. of ether. The solid collected by filtration and the remaining liquid ether was cooled at 0C, left to stand for 8 h and the still added with 0.05 moles of amyl nitrite and 0.08 crystalline solid, thus obtained, filtered. It was then moles of acetic acid. The solution was boiled for 30 washed carefully wi h water an ried n r vacuum, to evaporate about two-thirds of the solvent. Upon th obtaining tiny brownish needles. M.P. dilution with ether, another solid product was pre- 143C/deQ Yield 33% of the calculated Y pared which was added to the aforesaid; the whole was then washed with little ether and dried under EXAMPLE NO' 12 vacuum, thus obtaining a white solid under the form A Silver halide Photographic emulsion, Containing f hi i M P 174C/d Yi ld 124 g 1.8% moles ofsilver iodide and 98.2% of silver bromide equal to the 69.8% of the calculated yield. The product and having a silver-to-gelatin ratio of was divided was then purified upon crystallization from 75% 40 into Several P aqueous ethanoL Yield 0% A part thereof (called reference emulsion) was directly coated on a cellulose triacetate base and the other parts were added with the compounds shown in METHOD B table 3 in the quantities therein specified and finally 2,3-(3,4dimethyl-phenyl)-5-oxy-tetrazole-betaine coated on a cellulose triacetate base.

(Example No. 7) Samples of said emulsions were then exposed under a tungsten lamp and developed for 5' at 20C with a de- (M 5 Moles of 1,5 (3,4 dimethyl) phenyl 3 veloper having the following composition: nitroformazane were dissolved in 600 ml of chloro form. 0.11 moles of N-bromo-succinimide were then Memo] 2 2 added thereto slowly and the whole was heated up to Hydmquinone 2 60-70C. The red solution underwent a discoloration. Sodiurn Sulfie aflhydmus 72 g It was then cooled, poured into 2 l. of ether and a yelggg i l 'gr gg'g 5 low gummy solid separated. It was crystallized first Water to make 1 1 from ethanol/ether and then from 25% aqueous ethanol, thus obtaining long yellow prysms. MP. The same samples were fixed, washed and dried,then 166C/dec. Yield 35%. evaluated with a normal Densitometer.

Table 3 Quantity Fresh incubated Compound Solvent mM/M AgX A Sensitivity Fog A Sensitivity Fog 0.50 0.53 (a) DMF 0.05 0.12 0.28 0.15 0.25 (a) DMF 0.025 0.08 0.39 0.15 0.40 (a) DMF 0.0l0 0.06 0.39 0.14 0.45 (b) DMF 0.05 0.00 0.45 0.03 0.43 Ex. 1 DMF 0.05 +0.12 0.18 0.21 0.19 Ex. 2 DMF 2.0 +0.06 0.21 +0.10 0.24 Ex. 3 DMF 0.5 0.13 0.28 0.22 0.33

acetate bases. Samples of such emulsions were exposed under a tungsten lamp and developed for 24 seconds at 35C with a developer having the folb wing composition:

Potassium methabisulfite 42 g Potassium hydrate 47 g Hydroquinone 30 g Phenidone l.4 g Glutaraldehyde g Potassium bromide 3.9 g

Water to make 1 l Acetic acid to arrange the pH at 10.]

The same samples were fixed, washed and dried, then evaluated with a normal Densitometer.

Table 3 Continued Quantity Fresh incubated Compound Solvent mM/M AgX A Sensitivity Fog A Sensitivity Fog Ex. 4 DMF 2.0 0.05 0.22 0.00 0.23

Ex. 5 DMF 0.5 0.08 0.37 0.16 0.38

Ex. 6 DMF 0.5 0.05 0.32 0.08 0.35

Ex. 7 DMF 0.5 0.06 0.26 0.09 0.26

Ex. 8 DMF 0.5 0.02 0.31 0.02 0.32

Ex. 9 DMF 0.5 0.00 0.30 0.03 0.30

Ex. 10 DMF 0.l 0.06 0.28 0.03 0.31

Ex. ll DMF 0.5 .0.08 0.l8 0.l0 0.18

I This table shows the sensitometric results respectively obtained with a fresh film and with a filni incubated for 15 h at 72C and 30% R.H. The sensitivity is expressed in log E. The figures shown therein are sensitivity differences (A sens.) measured with respect to the reference emulsion.

EXAMPLE NO. l3 15 Table 5 A silver halide photographic emulsion having the n m same characteristics like that described in example 12 Compound Developer Deviloper Fog A sensitivity was divided into several parts- A part thereof (reference emulsion) was coated without any further addi- Ex I 4 25 I 00 '3; 000 tion on a cellulose triacetate base and the other parts 20 2 0,612 4 0,00 were added with the compounds shown in Table 4 in 2 22% 33 8-2; ggg the quantities therein specified and then coated on tri- 9 0:612

The compounds can he introduced into the bath by using a solvent as in the case of introduction into the emulsion. or not.

The silver halide photographic emulsions of the present invention are silver chloride, silver bromide and silver iodide emulsions and mixtures thereof such as for example silver bromoiodide and silver chlorobromide iodide. Such emulsions may include synthetic polymeric gelatin substitutes or additives, such as dextrane, polyvinyl alcohol, polyvinyl pyrrolidone, partially hydrolized polyvinyl acetate, polyethylacrylate, polymethylmethacrylate, polyamides, etc. The emulsions of the invention may be chemically sensitized with naturally active gelatine, by addition of chemical sensitizers Table 4 Fresh incubated Compound Solvent mM/M AgX A Sensitivity Fog A Sensitivity Fog 0.67 0.64 (a) DMF 0.05 0.29 0.46 0.34 0.36 (a) DMF 0.25 0.24 0.57 0.15 0.42 (a) DMF 0.10 O.17 0.59 0.l9 0.48 (b) DMF 0.05 0.05 0.57 0.09 0.55 Ex. 1 DMF 0.5 0.03 0.32 0.00 0.30 Ex. 2 DMF 0.5 0.l2 0.43 0.00 0.45 Ex. 3 DMF 0.5 0.03 0.36 0.00 0.39 Ex. 4 DMF 0.5 0.08 0.43 0.04 0.42 Ex. 5 DMF 2.0 0.06 0.48 0.03 0.45 Ex. 6 DMF 2.0 0.08 0.38 0.00 0.35 Ex. 7 DMF 0.5 0.04 0.38 0.00 0.40 Ex. 8 DMF 0.5 0.00 0.35 0.05 0.40 Ex. 9 DMF 0.5 0.08 0.41 0.03 0.41 Ex. 10 DMF 0.5 0.08 0.32 0.] 0.30 Ex. 1 l DMF 0.1 0.03 0.35 0.05 0.31

respect to their reference emulsion.

EXAMPLE NO. 14

The same samples were fixed, washed and dried, then evaluated with a normal Densitometer.

Table 5 also shows the obtained results.

such as thiourea, allylthiourea, thyocyanates, thiosulphates, etc. Sensitization may be effected by the addition of noble metals, such as gold salts. Spectral sensi tizers may be employed in emulsions of the invention, such as cyanine and merocyanine dyes. Moreover, the emulsions of the invention may include such additives as color couplers, filtering dyes, surfactants, hardeners, stabilizers, additional fog restrainers, plasticizers, antioxidizing agents, developing accelerators, etc. A photographic element comprises one support such as polyester, cellulose acetate, and the like and at least one layer including a silver halide emulsion layer of the above described type coated thereon. Such element can additionally contain other layers, that is, protective layers, interlayers, antihalo layers, filter layers, etc.

The tetrazolium C-oxy-betaine compounds of the invention may be conveniently introduced in the form of solutions into emulsions or any other coating composition during preparation thereof. Although it is generally preferred to incorporate the tetrazolium C-oxybetaine compounds of the invention directly into emulsion layers, these compounds may also be incorporated into layers adjacent the emulsion layers so that the silver halide emulsions are again in reactive association therewith. The tetrazolium C-oxy-betaine compounds are preferably introduced into photographic elements reactively associated with the silver halide emulsions in amounts ranging from about 0.05 to 3 mM/M of silver halide and most preferably from 0.1 to 2 mM/M of silver halide.

The processing baths of the present invention, as noted previously, may be photographic pre-baths, such as those known to the art to be useful prior to treatment of a silver halide photographic element with a developing solution, Predevelopment baths are usually (but not necessarily) acidic and may contain hardeners such as aldehydes and the like. The tetrazolium C-oxy-betaine compounds of the invention may, of course, also be employed in developing baths. Such baths are normally alkaline and include one or more silver halide photographic developing agents such as hydroquinone, metol, metolhydroquinone, phenidone, hydroquinonephenidone, and various p-phenylene diamine materials, the latter being useful in color development processes. The processing baths of the invention (prebaths and developer baths) preferably include from about 1 to mM/liter of solution and most preferably from 2 to 5 mM/liter of solution.

We claim:

1. A silver halide photographic emulsion having in reactive contact therewith at least a fog-inhibiting amount of a tetrazolium C-oxy-betaine compound.

2. A silver halide photographic emulsion having in reactive contact therewith at least a fog-inhibiting amount of a tetrazolium C-oxy-betaine compound corresponding to the formula 3. The emulsion of claim 1 wherein said antifogging compound is 2 ,3-di-phenyl-5-oxy-tetrazolium betaine.

4. The emulsion of claim 1 wherein said antifogging compound is 2,3-di(4-chloro-phenyl)5-oxytetrazolium betaine.

5. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(3-trifluoromethyl-phenyll5-oxytetrazolium betaine.

6. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(3-chloro-4-methyl-phenyl)S-oxytetrazolium betaine.

7. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(2-ethyl-phenyll5-oxy-tetrazolium betaine.

8. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(4-methyl-phenyll5-oxy tetrazolium betaine.

9. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(3,4-di-methyl-phenyll5-oxytetrazolium betaine.

10. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(2-acetyl-5-chloro-phenyl)5-oxytetrazolium betaine.

11. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(2-chloro-phenyll5-oxytetrazolium betaine.

12. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-( 3 ,4-di-chloro-phenyb5oxytetrazolium betaine.

13. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-( 3-methoxy-phenyll5 -oxytetrazolium betaine.

14. A silver halide photographic element having a silver halide emulsion layer and a fog-inhibiting amount of a tetrazolium C-oxy-betaine compound in reactive association therewith.

15. A silver halide photographic element having a silver halide emulsion layer and a fog-inhibiting amount of a tetrazolium C-oxy-betaine of formulas respectively corresponding to those referred to in claims 2 in reactive association therewith.

16. The photographic element of claim 14 wherein said tetrazolium C-oxy-betaine compound is contained in said emulsion layer.

17. The photographic element of claims 14 wherein said tetrazolium C-oxy-betaine compound is incorporated in a layer adjacent said silver halide emulsion layer. 

1. A SILVER PHOTOGRAPHIC EMULSION HAVING IN REACTIVE CONTACT THEREWITH AT LEAST A FOG-INHIBITING AMOUNT OF A TETRAZOLIUM C-OXY-BETAINE COMPOUND.
 2. A silver halide photographic emulsion having in reactive contact therewith at least a fog-inhibiting amount of a tetrazolium C-oxy-betaine compound corresponding to the formula
 3. The emulsion of claim 1 wherein said antifogging compound is 2 ,3-di-phenyl-5-oxy-tetrazolium betaine.
 4. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(4-chloro-phenyl)-5-oxy-tetrazolium betaine.
 5. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(3-trifluoromethyl-phenyl-5-oxy-tetrazolium betaine.
 6. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(3-chloro-4-methyl-phenyl-5-oxy-tetrazolium betaine.
 7. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(2-ethyl-phenyl-5-oxy-tetrazolium betaine.
 8. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(4-methyl-phenyl-5-oxy tetrazolium betaine.
 9. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(3,4-di-methyl-phenyl-5-oxy-tetrazolium betaine.
 10. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(2-acetyl-5-chloro-phenyl-5-oxy-tetrazolium betaine.
 11. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(2-chloro-phenyl-5-oxy-tetrazolium betaine.
 12. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(3,4-di-chloro-phenyl-5-oxy-tetrazolium betaine.
 13. The emulsion of claim 1 wherein said antifogging compound is 2,3-di-(3-methoxy-phenyl-5-oxy-tetrazolium betaine.
 14. A silver halide photographic element having a silver halide emulsion layer and a fog-inhibiting amount of a tetrazolium C-oxy-betaine compound in reactive association therewith.
 15. A silver halide photographic element having a silver halide emulsion layer and a fog-inhibiting amount of a tetrazolium C-oxy-betaine of formulas respectively corresponding to those referred to in claims 2 in reactive association therewith.
 16. The photographic element of claim 14 wherein said tetrazolium C-oxy-betaine compound is contained in said emulsion layer.
 17. The photographic element of claims 14 wherein said tetrazolium C-oxy-betaine compound is incorporated in a layer adjacent said silver halide emulsion layer. 